1. Technical Field
The present invention relates to a thermal cycler and a control method of the thermal cycler.
2. Related Art
Recently, with development of utilization technologies of genes, medical treatment utilizing genes such as gene diagnoses and gene therapies has attracted attention, and many techniques using genes for breed identification and breed improvement have been developed in agriculture and livestock fields. As technologies for utilizing genes, a technology such as a PCR (Polymerase Chain Reaction) method has been widespread. Today, the PCR method is an essential technology in elucidation of information of biological materials.
The PCR method is a technique of amplifying target nucleic acid by applying thermal cycling to a solution containing nucleic acid as a target of amplification (target nucleic acid) and reagent (reaction solution). The thermal cycling is processing of periodically applying two or more steps of temperatures to the reaction solution. In the PCR method, generally, thermal cycling of two or three steps is applied.
In the PCR method, generally, a container for biochemical reaction called a tube or a chip for biological sample reaction (biochip) is used. However, in the technique of related art, there have been problems that large amounts of reagent etc. are necessary, equipment becomes complex for realization of thermal cycling necessary for reaction, and the reaction takes time. Accordingly, biochips and reactors for performing PCR with high accuracy in short time using extremely small amounts of reagent and specimen have been required.
In order to solve the problem, Patent Document 1 (JP-A-2009-136250) has disclosed a biological sample reactor of performing thermal cycling by rotating a chip for biological sample reaction filled with a reaction solution and a liquid being immiscible with the reaction liquid and having a lower specific gravity than that of the reaction solution around a rotation axis in the horizontal direction to move the reaction solution.
Further, a RT-PCR (Reverse Transcription Polymerase Chain Reaction) method of performing transcription reaction with RNA (ribonucleic acid) as template and performing PCR on the produced cDNA (complementary deoxyribonucleic acid) has been known.
Reverse transcriptase enzyme used in the RT-PCR method is normally not heat-resistant enzyme, and may be deactivated when subjected to a high temperature. If the reverse transcriptase enzyme is deactivated and sufficient reverse transcription reaction becomes impossible, it is impossible to accurately perform the subsequent PCR, and the reaction accuracy of RT-PCR may be lower. Here, in order to shorten the time taken for the thermal cycling, it is preferable to preheat the thermal cycler. Patent Document 1 has disclosed an example having a container unit of the thermal cycler as a slit in which the chip for biological sample reaction is inserted from a side of one heater. When the chip for biological sample reaction is put into the slit, if there is a heater at an excessively high temperature, the reaction solution is subjected to the high temperature and the reverse transcriptase enzyme may be deactivated.